The completion of the Human Genome Project, which allows understanding of human diseases at the molecular level, identification of target molecules for diseases and further understanding of molecular mechanism of diseases, has opened an era of post-genomics. The information and insights obtained from human genomics are leading to technology for development of personalized medicine for human diseases. With personalized medicine, patients can be treated by selecting the appropriate drugs. Also, pharmacogenomic technology involving identification of biomarkers, targeted therapy, disease-specific mode of action of drugs, clinical and genomic information of patients, genome epidemic, and bioinformatic analysis should be complementarily integrated. In particular, technology involving prediction of the drug action in each individual, identification of diagnostic biomarkers, identification of novel target genes and proteins, and development of therapeutic agents are crucial for competitiveness in personalized medicine.
Recently, there has been fierce competition all over the world to identify therapeutic targets through research into the functions of genes related to generation and treatment of a serious disease such as cancer. The therapeutic targets can be used to diagnose cancer and develop new therapeutic agents. Along with such active genomic research, human genomic DNA chip or proteomic analysis has also been progressing, resulting in the finding of a large number of genes related to cancer and the accumulation of a database cataloging the various genes. However, since the particular biological functions in cells and relevance to cancer of most genes have not been fully discovered, in reality, the genes are still difficult to be used to confirm its relevance to cancer or used as diagnostic or target genes for cancer diagnosis.
Meanwhile, in response to increasing demand for research on the functions of various human genes, more attention is turning to a model organism for simple functional and morphological research. In order to understand evolutionarily well-preserved mechanisms fundamentally occurring in cells, there has been process in studying the application of model organisms, which have long had various applications, to diagnose cancer or identify therapeutic targets.
RNA interference (RNAi) is a powerful tool for clearly identifying genes that are overly expressed in cancer cells as possible targets for treating cancer. RNAi triggers sequence-specific degradation of mRNA homologous with a base sequence of interest in cells using various forms of oligo double-stranded RNAs (oiligo dsRNAs), such as microRNAs (miRNAs), expressed dsRNAs and synthetic small interference RNAs (siRNAs), such that the function of the gene is suppressed. Target validation as a cancer target is carried out by examining phenotypical changes of the cells inhibited in gene expression to identify the function of the corresponding gene and signal transmission pathways, which is used to develop novel drugs.
Among the oligo dsRNAs capable of being used for RNAi, a siRNA-mediated technique (pathway) has drawn attention in recent times for being a phenomenal tool, and was even named the “breakthrough of the year” by the Journal of Science (2002). siRNA is a short dsRNA having 19 to 23 bps. Once introduced into a cell, it exhibits a specific inhibition effect on a specific gene. siRNA that is complementary to a gene activating generation of cancer and inhibiting apoptosis would inhibit the function of the gene in cells, thereby killing cancer cells and validating a target gene for treating cancer. Thus, siRNA study has been actively conducted for identification of a disease-specific target gene, target gene validation, and therapeutic agent development.
Meanwhile, the FLJ25416 genes (GenBank Accession NOs: FLJ25416 and FLJ13936, UniProtKB/TrEMBL entry Q8IXT1) are genes for hypothetical proteins whose functions are not yet known.